1. Field of the Invention
The invention relates to an apparatus for recording a first and a second digital information signal in slant tracks on a magnetic record carrier, the apparatus comprising
input means for receiving the first and second digital information signals,
signal processing means for processing the first and second digital signals into first and second trick play signals, respectively, suitable for recording in the tracks,
writing means for writing, at a recording speed of the record carrier, the first and second trick play signals so as to obtain trick play segments located at specific positions in said tracks, the writing means comprising at least a first and a second write head located on a rotatable head drum, the first write head having a gap with a first azimuth angle, and the second write head having a gap with a second azimuth angle which is different from the first azimuth angle, the first digital information signal being meant for enabling a replay in a reproduction apparatus at a trick play reproduction speed which equals n1 times the recording speed, the second digital information signal being meant for enabling a replay in said reproduction apparatus at a trick play reproduction speed which equals n2 times the recording speed, where n1 and n2 are integers unequal to each other and unequal to 0 and 1.
2. Description of the Related Art
Such a recording apparatus is known from U.S. Pat. No. 5,751,889, corresponding to International Application WO 95/28061, document D4 in the list of documents. The known apparatus takes the form of a digital video recorder for recording a digital video signal. The digital video signal may be in the form of an MPEG-encoded video signal, in which packets of information of the digital video signal are included in the serial data stream of the MPEG-encoded video signal. In addition to such MPEG encoded video signal, a trick play signal can be recorded in the tracks on the record carrier. Such trick play signal can be the same video signal, but reproduced at a record carrier (trick play) speed which is other than the nominal reproduction speed. Generally, a separate datastream is recorded as the trick play signal on the record carrier for enabling the reproduction at such trick play speed. The trick play signal can be derived from the MPEG-encoded video signal, e.g. by selecting I-frames from the MPEG-encoded video signal.
This trick play signal, however, need not necessarily be a trick play signal that has a relationship with the MPEG-encoded video signal, but can be a completely different signal. But, in the same way as the MPEG-encoded digital video signal, the serial datastream of the trick play signal comprises packets of information of the trick play signal.
The document mentioned above describes the recording of segments of information of a plurality of trick play signals in the tracks on a record carrier. The segments of a specific trick play signal have a specific position in the tracks in order to enable reproduction of the trick play signal at its corresponding trick play reproduction speed.
It is an object of the invention to propose an improved recording apparatus for recording a plurality of trick play signals in accordance with a specific format on the record carrier.
The recording apparatus in accordance with the invention is characterized in that the first and second trick play signals comprise sync blocks of information of the first and second digital information signals, respectively, and that the writing means are adapted to write the sync blocks of the first trick play signal into first trick play segments, and to write the sync blocks of the second trick play signal into second trick play segments, so as to enable, during reproduction at a trick play speed n1 times the recording speed in said reproduction apparatus, which is provided with reading means for reading the first and second trick play segments, said reading means comprising at least a first and a second read head located on a rotatable head drum, said first read head having a gap with an azimuth angle substantially equal to said first azimuth angle, and the second read head having a gap with an azimuth angle substantially equal to said second azimuth angle, the reading of m1 sync blocks of the first trick play signal from first trick play segments during one revolution of the head drum and so as to enable, during reproduction at said trick play speed n2 times the recording speed, and the reading of m1 sync blocks of the second trick play signal from second trick play segments during one revolution of the rotatable head drum, where m1 is an integer larger than 1.
The invention is based on the recognition that in this way, the same number of sync blocks can be read for at least two different trick play reproduction modes, such as, the trick play reproduction modes with a certain speed larger than the recording speed, and in the forward and backwards direction. The invention enables further measures to be taken so that various other advantages can be obtained, such as, a very robust reproduction in a trick play reproduction mode, namely, by optimally positioning the trick play segments along scanning lines of the read heads. An optimal robustness against tracking errors and missing sync blocks can be obtained. Further, an optimal detection of subcode information stored in a subcode area can be realized.